ASU Electronic Theses and Dissertations
This collection includes most of the ASU Theses and Dissertations from 2011 to present. ASU Theses and Dissertations are available in downloadable PDF format; however, a small percentage of items are under embargo. Information about the dissertations/theses includes degree information, committee members, an abstract, supporting data or media.
In addition to the electronic theses found in the ASU Digital Repository, ASU Theses and Dissertations can be found in the ASU Library Catalog.
Dissertations and Theses granted by Arizona State University are archived and made available through a joint effort of the ASU Graduate College and the ASU Libraries. For more information or questions about this collection contact or visit the Digital Repository ETD Library Guide or contact the ASU Graduate College at gradformat@asu.edu.
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- Creators: Mobasher, Barzin
- Creators: Chassin, Laurie
Description
Layer-wise extrusion of soft-solid like cement pastes and mortars is commonly used in 3D printing of concrete. Rheological and mechanical characterization of the printable binder for on-demand flow and subsequent structuration is a critical challenge. This research is an effort to understand the mechanics of cementitious binders as soft solids in the fresh state, towards establishing material-process relationships to enhance print quality. This study introduces 3D printable binders developed based on rotational and capillary rheology test parameters, and establish the direct influence of packing coefficients, geometric ratio, slip velocities, and critical print velocities on the extrudate quality. The ratio of packing fraction to the square of average particle diameter (0.01-0.02), and equivalent microstructural index (5-20) were suitable for printing, and were directly related to the cohesion and extrusional yield stress of the material. In fact, steady state pressure for printing (30-40 kPa) is proportional to the extrusional yield stress, and increases with the geometric ratio (0-60) and print velocity (5-50 mm/s). Higher print velocities results in higher wall shear stresses and was exponentially related to the slip layer thickness (estimated between 1-5μ), while the addition of superplasticizers improve the slip layer thickness and the extrudate flow. However, the steady state pressure and printer capacity limits the maximum print velocity while the deadzone length limits the minimum velocity allowable (critical velocity regime) for printing. The evolution of buildability with time for the fresh state mortars was characterized with digital image correlation using compressive strain and strain rate in printed layers. The fresh state characteristics (interlayer and interfilamentous) and process parameters (layer height and fiber dimensions) influence the hardened mechanical properties. A lower layer height generally improves the mechanical properties and slight addition of fiber (up to 0.3% by volume) results in a 15-30% increase in the mechanical properties. 3D scanning and point-cloud analysis was also used to assess the geometric tolerance of a print based on mean error distances, print accuracy index, and layer-wise percent overlap. The research output will contribute to a synergistic material-process design and development of test methods for printability in the context of 3D printing of concrete.
ContributorsAmbadi Omanakuttan Nair, Sooraj Kumar (Author) / Neithalath, Narayanan (Thesis advisor) / Rajan, Subramaniam (Committee member) / Mobasher, Barzin (Committee member) / Hoover, Christian (Committee member) / Chawla, Nikhilesh (Committee member) / Arizona State University (Publisher)
Created2021
Description
Alcohol use disorder (AUD) causes immense global burden and has a significant impact on economic and societal functioning. Efficacious treatments for AUDs have been well-established within the literature, however the most commonly accessed treatments for AUD are alcohol-related services, such as self-help groups, outpatient clinics, and detoxification centers. Though studies suggest these services are effective at treating AUDs, there are numerous differences between individuals who receive alcohol-related services and individuals who do not, causing selection bias. Furthermore, current studies of alcohol-related services frequently define recovery outcomes as abstinence, which reduces variability in viable recovery outcomes, such as reduction of drinking behaviors. In addition, reduction in drinking and alcohol-related problems should theoretically have an impact on broader aspects of functioning, such as familial functioning. Improved familial context may reduce risk to family members, who are otherwise at heightened risk for emotional and behavioral problems when living with a family member with AUD. The current study investigated the effect of alcohol-related services on binary and continuous drinking outcomes after eliminating selection bias using multiple propensity score approaches, to identify the best methodology for a high-risk community sample of individuals with AUD. Propensity scores were created using logistic regression approaches and boosted regression trees. Matching, weighting, and subclassification were used, and matching was performed both using greedy and global approaches. Results suggested subclassification was the most successful method for real world alcohol-related services samples with moderate sample size. Moreover, findings demonstrated that boosted regression approaches were less successful than logistic regression approaches at minimizing the effects of selection bias on known confounding variables that are highly related to group selection. In addition, after removing the effects of selection bias, there were no significant difference between participants who received alcohol-related services and the comparison control group on drinking or family functioning, though both groups reduced drinking from pre- to post-alcohol-related services receipt. Findings suggest careful selection of quasi-experimental methods is warranted in real-world samples, to ensure optimal removal of selection bias. Moreover, future studies should continue to clarify the profile of individual that benefits from alcohol-related services to inform intervention efforts.
ContributorsSternberg, Ariel (Author) / Chassin, Laurie (Thesis advisor) / Corbin, William (Committee member) / Meier, Madeline (Committee member) / Grimm, Kevin (Committee member) / Arizona State University (Publisher)
Created2021
Description
Despite the established co-prevalence of substance use (SU) and disordered eating (DE), few longitudinal studies have sought to examine their shared development. Findings have been inconsistent within the extant literature. This may be attributable in part to several methodological aspects, including overlooking distinct psychopharmacological properties of common substances of abuse, examining only between-person relations, and failing to account for shared risk factors. The current study sought to address these gaps by applying latent curve models with structured residuals (LCM-SR) to a preexisting, national sample of adolescent girls followed into adulthood, Add Health. In Aim 1, between-person effects examined the simultaneous development of alcohol, tobacco, and marijuana use and DE behaviors in substance-specific models. In Aim 2, bivariate latent curve models were expanded to account for within-person effects (LCM-SR) in order to examine the potentially bidirectional, prospective relationship between use of a specific substance and DE. Lastly, models accounted for shared developmental risk factors. Findings of the current study demonstrate preliminary evidence of substance-specific effects with DE emerging in adolescence. Across model-building steps, DE engagement in early adolescence was significantly associated with growth in tobacco use and marginally associated with marijuana use. Appetitive side-effects of both substances may link use with DE behaviors and enhance instrumental use for weight control. Significant associations did not emerge between alcohol and DE, and results of the conditional model indicate this co-occurrence is best explained by third variable mechanisms. Implications for prevention are discussed.
ContributorsBruening, Amanda B (Author) / Corbin, William (Thesis advisor) / Chassin, Laurie (Committee member) / Meier, Madeline (Committee member) / McNeish, Daniel (Committee member) / Arizona State University (Publisher)
Created2021
Description
Composite materials have gained interest in the aerospace, mechanical and civil engineering industries due to their desirable properties - high specific strength and modulus, and superior resistance to fatigue. Design engineers greatly benefit from a reliable predictive tool that can calculate the deformations, strains, and stresses of composites under uniaxial and multiaxial states of loading including damage and failure predictions. Obtaining this information from (laboratory) experimental testing is costly, time consuming, and sometimes, impractical. On the other hand, numerical modeling of composite materials provides a tool (virtual testing) that can be used as a supplemental and an alternate procedure to obtain data that either cannot be readily obtained via experiments or is not possible with the currently available experimental setup. In this study, a unidirectional composite (Toray T800-F3900) is modeled at the constituent level using repeated unit cells (RUC) so as to obtain homogenized response all the way from the unloaded state up until failure (defined as complete loss of load carrying capacity). The RUC-based model is first calibrated and validated against the principal material direction laboratory tests involving unidirectional loading states. Subsequently, the models are subjected to multi-directional states of loading to generate a point cloud failure data under in-plane and out-of-plane biaxial loading conditions. Failure surfaces thus generated are plotted and compared against analytical failure theories. Results indicate that the developed process and framework can be used to generate a reliable failure prediction procedure that can possibly be used for a variety of composite systems.
ContributorsKatusele, Daniel Mutahwa (Author) / Rajan, Subramaniam (Thesis advisor) / Mobasher, Barzin (Committee member) / Neithalath, Narayanan (Committee member) / Arizona State University (Publisher)
Created2021
Description
Negative Urgency and Positive Urgency are important subfacets of a propensity to rash action. There is currently limited research on parental antecedents of Negative Urgency and Positive Urgency. The current study investigated whether parent personality and parenting behaviors predict adolescent Negative Urgency and Positive Urgency. Data were taken from a community sample with parent personality, positive parenting behaviors, and child Negative Urgency and Positive Urgency measured at separate timepoints. Structural equation models were used to examine whether parent personality predicted adolescent Negative Urgency and Positive Urgency and whether positive parenting mediated this relationship. There was no evidence for a relationship between parent personality and children’s Negative Urgency and Positive Urgency. In addition, there was no relationship between parenting behaviors and child Negative and Positive Urgency in cross-reporter models, but child-reported parenting predicted later adolescent-reported Negative and Positive Urgency. Greater positive parenting, as perceived by children, was related to less Negative and Positive Urgency when they were adolescents. More research is needed to understand whether the current results are due to reporter bias or whether child-perceived parenting behaviors influence the development of adolescent Negative and Positive Urgency.
ContributorsBui, Leena (Author) / Chassin, Laurie (Thesis advisor) / Corbin, William (Committee member) / Lemery-Chalfant, Kathryn (Committee member) / McNeish, Daniel (Committee member) / Arizona State University (Publisher)
Created2022
Description
Excessive drinking in adolescence is a public health issue with major consequences on both an individual and societal level. Elucidating genetic and environmental influences could be particularly informative for prevention efforts. One potential source of genetic influence is sensitivity to environmental influences. It was hypothesized that parent knowledge would interact with genetic sensitivity to the environment to indirectly reduce risk for alcohol problems through less adolescent rule breaking behavior. Participants (N=316) provided genetic data and reported their rule breaking behavior and past year frequency of heavy drinking, and participants’ custodial parents reported their perceived knowledge of their child’s activities. A novel index of genetic sensitivity to environmental influence was created using published methylation quantitative trait locus data from the frontal lobe. Study hypotheses were mostly not supported. The study results likely reflect the poor distribution of study variables and the limitations of the current study’s sensitivity gene score. The current study underscored the importance of adhering to methodological rigor and explored alternate conceptualizations and methods that future research could use to elucidate the role of inherited to sensitivity to environmental influences in adolescent drinking.
ContributorsPandika, Danielle Mutiara (Author) / Chassin, Laurie (Thesis advisor) / Elam, Kit (Committee member) / Lemery-Chalfant, Kathryn (Committee member) / Edwards, Michael (Committee member) / Arizona State University (Publisher)
Created2020
Description
Alkali-activated aluminosilicates, commonly known as "geopolymers", are being increasingly studied as a potential replacement for Portland cement. These binders use an alkaline activator, typically alkali silicates, alkali hydroxides or a combination of both along with a silica-and-alumina rich material, such as fly ash or slag, to form a final product with properties comparable to or better than those of ordinary Portland cement. The kinetics of alkali activation is highly dependent on the chemical composition of the binder material and the activator concentration. The influence of binder composition (slag, fly ash or both), different levels of alkalinity, expressed using the ratios of Na2O-to-binders (n) and activator SiO2-to-Na2O ratios (Ms), on the early age behavior in sodium silicate solution (waterglass) activated fly ash-slag blended systems is discussed in this thesis. Optimal binder composition and the n values are selected based on the setting times. Higher activator alkalinity (n value) is required when the amount of slag in the fly ash-slag blended mixtures is reduced. Isothermal calorimetry is performed to evaluate the early age hydration process and to understand the reaction kinetics of the alkali activated systems. The differences in the calorimetric signatures between waterglass activated slag and fly ash-slag blends facilitate an understanding of the impact of the binder composition on the reaction rates. Kinetic modeling is used to quantify the differences in reaction kinetics using the Exponential as well as the Knudsen method. The influence of temperature on the reaction kinetics of activated slag and fly ash-slag blends based on the hydration parameters are discussed. Very high compressive strengths can be obtained both at early ages as well as later ages (more than 70 MPa) with waterglass activated slag mortars. Compressive strength decreases with the increase in the fly ash content. A qualitative evidence of leaching is presented through the electrical conductivity changes in the saturating solution. The impact of leaching and the strength loss is found to be generally higher for the mixtures made using a higher activator Ms and a higher n value. Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR) is used to obtain information about the reaction products.
ContributorsChithiraputhiran, Sundara Raman (Author) / Neithalath, Narayanan (Thesis advisor) / Rajan, Subramaniyam D (Committee member) / Mobasher, Barzin (Committee member) / Arizona State University (Publisher)
Created2012
Description
This study aimed to advance understanding of the relation between social media and adolescent alcohol use while accounting for offline peer alcohol use, exploring offline peer alcohol use separately as a covariate and as a moderator, with an additional exploratory analysis of the relation between social media and alcohol use without offline peer alcohol use in the model. A total of 868 students (55% female) in grade 7 (n = 468) and grade 8 (n = 400) at wave 1, self-reported on alcohol use, binge drinking, and social media use as well as nominated friends from their school and grade. Data from nominated peers who also completed the questionnaires were used for peer-report of alcohol use. Data were collected annually from students at grades 8, 9, 10, and 11 were used in analyses. Final structural models consisted of a cross-lagged panel design with saved factor scores for social media and peer alcohol use predicting a categorical alcohol use variable or a binary binge drinking variable. With offline peer alcohol use as a covariate in the model, social media did not prospectively relate to subsequent grade alcohol use or binge drinking. However, without offline peer alcohol use, the path from social media use to subsequent grade alcohol use was significant but not the path to binge drinking. Offline peer alcohol use did not significantly moderate the relation between social media and subsequent grade alcohol use or binge drinking.
ContributorsCurlee, Alexandria Stephanie (Author) / Corbin, William R. (Thesis advisor) / Chassin, Laurie (Committee member) / Doane, Leah D (Committee member) / Grimm, Kevin J. (Committee member) / Arizona State University (Publisher)
Created2020